A digital camera (inclusive of a mobile telephone having a camera function) is provided with various setting devices such as a mode dial for setting a shooting mode and a playback mode and the like, and a focus switch for setting types of focus such as manual focus and autofocus. When the power supply of the digital camera is turned off and the camera is placed in a bag or the like, it may happen that these setting devices are subjected to impact and moved, causing a change in set state. When the power supply of the digital camera is then turned on and an attempt is made to take a picture, the user may not know that there has been a change in the set state. For this reason, there is an apparatus that checks to determine whether there is a mismatch in set state between that which was in effect when the operating power supply was turned off and that in effect when the power supply is subsequently turned on, and warns of a change in operating state when it is determined that a mismatch has occurred (Patent Document 1).
Also available are an apparatus for inferring a change in operating environment and initializing settings and status based upon the result (Patent Document 2); an apparatus which, if there is an idle time interval following a previous imaging operation, prevents the user from forgetting to set shooting conditions the next time imaging is performed (Patent Document 3); an apparatus that notifies the user of an error that occurred when the power supply was turned off (Patent Document 4); and an apparatus that prevents an erroneous setting of the camera mode (Patent Document 5).